Defective latch needle detector and control network therefor

ABSTRACT

Means for detecting defective latch needle condition in a knitting machine wherein an electrically non-conductive feeler is mounted in the path of movement of the needles so as to be deflected by any latches in defective condition. The feeler is insulatingly carried by a coil having a core mounted therewithin and insulated therefrom. The core and coil define a normally open electrical switch which is closed when the feeler is deflected by a defective latch needle. A control network is provided and is responsive to the closing of the switch for interrupting the energization of the drive means for the knitting machine. The control network provides sufficient power for lighting as many detector lamps as are activated at one time, while still providing the requisite power for interrupting the energization of the knitting machine drive means.

United States Patent Tellerman et al.

[54] DEFECTIVE LATCH NEEDLE DETECTOR AND CONTROL NETWORK THEREFOR [72] Inventors: Edward M. Tellerman, East Rockaway; Jose Castillo Deniega, Elmhurst, both of NY.

[73] Assignee: Stop-Motion Devices Corporation,

. Plainview, NY.

[22] Filed: March 15, 1971 [21] Appl. No.: 124,321

[52] US. Cl ..66/157 [51] Int. Cl. ..D04b 35/18 [58] Field of Search.....66/l57, 165, 163; ZOO/61.14, 200/61 .18

[56] References Cited UNITED STATES PATENTS 481,726 8/ l 892 Clute ..66/ 163 2,481,632 9/1949 f Vossen ..66/157 2,948,076 8/ 1960 Patricello ..200/61.18 X 3,323,333 6/1967 Vossen ..66/165 X 3,390,548 7/1968 Rogerson et al ..66/157 X 3,509,739 5/1970 Gottschall ..66/ 157 3,602,727 8/ 1971 Schwalm ..66/ 157 Sept. 12, 1972 FOREIGN PATENTS OR APPLICATIONS 1,927,982 1/1970 Germany ..66/163 16,349 1913 Great Britain ..66/163 703,846 2/1954 Great Britain ..66/157 Primary ExaminerWm. Carter Reynolds Attorney-Henry R. Lerner ABSTRACT Means for detecting defective latch needle condition in a knitting machine wherein an electrically non-conductive feeler is mounted in the path of movement of the needles so as to be deflected by any latches in defective condition. The feeler is insulatingly carried by a coil having a core mounted therewithin and insulated therefrom. The core and coil define a normally open electrical switch which is closed when the feeler is deflected by a defective latch needle. A control network is provided and is responsive to the closing of the switch for interrupting the energization of the drive means for the knitting machine. The control network provides sufficient power for lighting as many detector lamps as are activated at one time, while still providing the requisite power for interrupting the energization of the knitting machine drive means.

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DEFECTIVE LATCH NEEDLE DETECTOR AND CONTROL NETWORK THEREFOR BACKGROUND OF THE INVENTION This invention relates to knitting machines, particularly circular knitting machines in which the latches of the latch needles must remain open during the knitting operation or operations thereof. In the event that such latches are not fully opened as required, and the knitting machine continues to operate, the product being knit will be defective and essentially worthless. Accordingly, it is of prime importance to detect a closed latch and to thereupon stop the operation of the knitting machine, thus preventing the production of faulty goods or products, as well as avoiding the waste of valuable machine time.

The detection of such undesired closed latches was originally effectuated in theprior art by providing a feeler in the path of movement of any closed latches so that upon engagement thereby the feeler would be displaced causing, ultimately, the mechanical closing of a switch to interrupt the machine motor.

With the advent of more sophisticated electronic circuitry, detection of a closed latch was accomplished by the electrical contact between feeler and closed latch which in turn would energize the gate of an electronic gate controlled device, such as a thyristor, to provide sufficient current for energizing a relay which in turn causes the de-energization of the knitting machine motor. Recent examples of such closed latch detectors are shown in US. Pat. Nos. 3,397,556 and 3,509,739. In the devices of these patents, it is the electrical contact between feeler and closed latch which energizes the gate circuit transistor amplifying device, such as a thyristor, to in turn interrupt or de-energize the knitting machine motor.

While reliance on a thyristor has enabled the obtaining of a shorter response time and also enabled a more compact device, the accompanying dependency on a feeler for an electrical contact has had a lesser satisfactory result. More specifically, such electrical contact between feeler and closed latch produces undesirable effects, such as sparking, and requires the latch to be electrically related to the feeler, creating additional complications and requirements in the wiring of the knitting machine. More significant, however, is the fact that the prequisite electrical contact between feeler and closed latch has proved to be insufi'iciently reliable. For example, both the needles, and the feelers to a lesser extent, are exposed to oil splashing which may clothe either or both of these elements with an electrically insulating layer. Thus, while there may be physical contact between closed latch and feeler, if either or both is sufficiently covered with oil, there may be no ensuing electrical contact. More probable than the possibility of oil or other lubricant providing an insulating coatingto feeler or latch, is the likelihood of lint or other foreign matter gathering about the feeler or latch, defining insulators and preventing electrical contact as required.

Furthermore, the accumulation by the needle of lumps of fuzz from threads and yarns, even where the latch is open, is an undesirable condition of the latch needle which should lead to the interruption of the knitting machine in order to protect the needles from damage. Conventional closed latch detectors referred to above do not detect this condition of the latch needles, since such condition occurs even when the latch is properly open, making it necessary for equipping the knitting machine with separate needle protectors, such as, for example, those shown in US. Pat. No. 3,323,333, assigned to the assignee hereof.

It is usual to provide a knitting machine with a plurality of closed latch needle detectors, the activation of any one of which is intended to energize a relay which activates the stop motion. Since each detector is usually provided with its own light, the simultaneous activation of a plurality of detectors causes a substantial current flow from the power supply and through the .cornrnon stop motion relay. This creates a serious problem in relay selection in order to preserve the proper relay sensitivity.

The disadvantages of the prior art devices, as described above, have been substantially eliminated by the present invention.

SUMMARY OF THE INVENTION In accordance with the present invention, an improved defective latch needle detector is provided, which also constitutes an improvement over prior US. Pat. No. 2,896,037, issued July 21, 1959, assigned to the assignee hereof.

More specifically, the detector of the present invention includes a resilient feeler which is placed in the path of movement of any closed latches. The resilient feeler is carried at one end of a coil spring which is provided with an internal core held in spaced relation therewith by an insulating sleeve. The coil spring and core define a normally open switch when the feeler remains undeflected, which is the normal condition when the latches are open. When one or more latches are not fully opened, the feeler will be deflected thereby, in turn flexing the coil spring and causing the latter to make contact with the core, thus closing the switch and activating the control circuitry for the stop motion and interrupting the drive motor of the knitting machine.

Thus, it is the mechanical deflection of the feeler which causes electrical contact between coil and core, which mechanical deflection avoids sparking, and takes place whether or not there is electrical contact between the feeler and the closed latch.

Further, even when the latch of a needle is properly open, but such needles has accumulated thereon an excessive quantity of lumps of fuzz, these lumps will find the feeler in their path of movement and thus deflect the feeler to activate the stop motion. Accordingly, the present detector is not only activated upon the occurrence of a closed latch, but also upon the occurrence of a defective latch needle, whose latch is open, but which has accumulated thereon an excessive amount of lumps of fuzz. Thus, the detector herein acts both as a closed latch detector and as a needle protector.

Further, in accordance with the invention, the switch defined by the coil and core energizes a control circuit which includes an electronic gate controlled device for providing instantaneous activation of the stop motion.

Another object of the invention is the provision of a power pack which furnishes the requisite amount of current for lighting the lamp associated with each detector, regardless of how many detectors are simultaneously activated, while at the same time providing the proper amount of current for controlling a relay of sufficient sensitivity for operating the stop motion.

Another object is the provision of a power pack for the closed latch detector control circuit which is compatible with other faulty yarn detectors normally provided on the same knitting machines.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an elevation view of a portion of a knitting machine provided with a faulty latch needle detector in accordance with the invention;

FIG. 1a is a fragmentary view similar to FIG. 1 showing another defective condition of the latch needle;

FIG. 2 is a longitudinal section of the detector taken along line 22 of FIG. 1, on an enlarged scale, showing the feeler in its normal, undeflected, condition;

FIG. 3 is a fragmentary view similar to FIG. 2 and also showing the feeler in deflected condition due to engagement thereof by a defective latch needle;

FIG. 4 is a circuit diagram showing the circuitry associated with the detector in accordance with the invention;

FIG. 4a is a modification of the circuit diagram shown in FIG. 4;

FIG. 5 is a circuit diagram showing a power pack used in conjunction with detectors in accordance with the invention; and

FIG. 6 is another embodiment of a power pack used in conjunction with detectors in accordance with the invention.

DESCRIPTION OF PREFERRED EMBODIMENT Referring to FIG. 1, there is shown a conventional knitting machine latch needle 10 whose butt 12 is received in cam track 14 defined in cam 16 of cam box 18. Rotation of needle cylinder 20 of the knitting machine will provide, in a conventional manner, the desired axial movement of latch needle 10, as dictated by the associated cam.

The detector 22 in accordance with the invention is supported on stationary cam box 18 by conventional mounting means 24. As shown in FIG. 1, latch needle 10 includes a latch 26 shown in full lines in its normal fully opened condition and in dashed lines in its undesired closed condition intended to be detected. Detector device 22 is mounted so that its feeler 28 is in the path of latch 26 when in its closed condition, as well as in the path of an accumulation of lumps of fuzz 27 on latch needle 10, though its latch 26 is open, as best shown in FIG. 1a.

Referring now to FIG. 2, it is seen that detector 22 comprises a generally tubular housing 30 provided at one end thereof with a bushing 32 apertured at 34 to receive a coil spring 36, a portion of which extends outwardly of bushing 32. Coil spring 36 is retained within bushing 32 by means of sleeve 38 which also retains core 40 therewithin, in spaced relation with coil spring 36. The outer end of coil spring 36 is closed by plug 42 which carries the feeler 28.

Core 40 and coil spring 36 define a normally open electrical switch when feeler 28 is in its undeflected position, as shown in FIG. 2. Accordingly, bushing 32 and sleeve 38 are made of electrically insulating material to prevent electrical contact between core 40,

spring 36 and housing 30 when the feeler is undeflected. Plug 42 is also made of insulating material to prevent electrical contact between feeler 28 and spring 36.

A compartment 44 is defined between flange 46 and the other end of housing 30. Such compartment houses a lamp 48 which partially projects outwardly of housing 30, and is provided with a lens 50 whose rim 52 carries reset ring 54. Compression spring 56 biases rim 52 and ring 54 against end ring 58 affixed to housing 30. With this arrangement, depression of lens 50 against the spring action displaces reset ring 54 from engagement with end ring 58. Thus, rings 54 and 58 define a normally closed switch whose function will be more fully discussed hereafter.

Housing 30 also defines a compartment 60, between flange 46 and bushing 32 wherein there are housed the various electrical and electronic components which will be more fully discussed hereafter. Lead wire 62 extends from compartment 60 outwardly through opening 64 in housing 30.

The operation of detector 22 is best shown with reference to FIG. 3 wherein the solid lines show the position of feeler 28 and coil spring 36 during normal operating condition and wherein the dashed lines show their positions when the feeler is deflected in response to engagement by a closed latch, or by a needle whose latch is open but which has accumulated thereon an excess of lumps of fuzz. For the purpose of this specification, a needle having a closed latch or a needle having an open latch but having accumulated thereon an excess of lumps of fuzz shall be referred to as a needle having a defective condition. The engagement of feeler 28 by a needle in defective condition deflects the feeler which in turn flexes coil spring 36 whose turns will contact core 40, thus closing the switch defined by the spring and the core. The closing of such switch as will hereafter be seen, activates the stop motion for the knitting machine to interrupt the drive motor thereof.

As evident from FIG. 3, it is the mechanical deflection of feeler 28 which causes the accompanying electrical contact between coil spring 36 and core 40. Thus, it makes no difference whether there is good electrical contact between feeler 28 and closed latch 26, and the detector will be operative when either or both closed latch 26 and feeler 28 are electrically insulated from each other by oil, lint, or any foreign matter likely to gather about either the feeler or the latch. Furthermore, feeler 28, being insulatingly mounted by plug 42 will eliminate sparking between feeler and closed latch, even when they are not electrically insulated from each other by foreign matter. Further, since detection is not dependent on electrical contact between latch and feeler 28, the latter need not be made of an electrically conductive material. Spring 36 is closely wound and of small diameter, as for example 0.125 inches so that the radial distance between core 40 and spring 36 is of such small magnitude that deflection of feeler 28 causes near instantaneous engagement of core and spring.

The operation of the detector will now be described by reference to FIG. 4 which shows the simplest kind of control circuitry therefor. In FIG. 4, the dashed lines A represent the portion of the circuitry located within detector device 22 which includes lamp 48, normally closed reset switch defined by reset ring 54 and end ring 58, the normally open detector switch defined by spring 36 and'core 40, as well as thyristor 66, resistors 68 and 70 and condenser 72. The housing 30 is grounded as at G and lead wire 62 is connected to a relay 74, the other end of which is connected to negative terminal 76 of a power supply whose positive terminal 78 is grounded. When relay 74 is unenergized, switch 80 is in the position shown in FIG. 4 in which condition motor M of the knitting machine is energized, and when relay 74 is energized, it will cause the opening of normally closed switch 80 to interrupt motor M. v V

When the knitting machine is operating satisfactorily, i.e., without the presence of any latch needles in defective condition, switch 36-40 is open and there is no current flow through thyristor 66 and thus no energization of relay 74. Upon closing'of switch 36-40, in response tovthe engagement of feeler 28 by a closed latch, current flow is established as follows: from positive terminal 78 to ground, through reset switch 54-58, through lamp 48, through closed switch 36-40, through the controlelectrode and the cathode of thyristor 66, through conductor 62, relay 74 and to negative terminal 76. Such current flow will immediately trigger thyristor 66 to maintain continuous current flow therethrough and through lamp 48. Such continuous current flow will be maintained, regardless of the reopening of switch 36-40, until reset switch 54-58 is opened. The current flow thus established through the circuitry in A energizes relay 74,'thus opening switch 80 and interrupting current flow to the motor whose rotation is thus discontinued. Resistor 68 serves the purpose of insuring current flow in the event that lamp 48 burns out and bias resistor 70 and condenser 72 prevent thyristor 66 from being accidentally triggered in'response to transient currents unrelated to the closing of switch 36-40.

In accordance with a modification of the invention, core 40 may be a permanent magnet and coil 36 may be made of magnetic material so that upon deflection of feeler 28 causing coil spring 36 to engage core 40, such engagement will be maintained as a result of the magnetic attraction between core and coil. Under this arrangement, once switch 36-40 is closed, it will remain closed until coil and core are physically separated after the defect has been corrected. Such magnetic relationship for switch 36-40 makes the use of a thyristor and of a reset switch unnecessary.

5 It will be understood that a knitting machine will normally be equipped with a plurality of detectors, all of which have circuitry identical to A and in parallel with each other. Accordingly, the engagement of the feeler in any one of the detectors will be effective to energize relay 74 and de-energize motor M. It will be appreciated, from FIG. 4, that a minimal amount of curlet us further assume that a relay having a resistance of 120 ohms is chosen. Under this arrangement, if one lamp is lit, then the 12 volts will be distributed relatively evenly between relay and lamp, providing sufficient current for lighting the lamp and activating the relay. If, however, six detectors are activated simultaneously, then the equivalent resistance of the six lamps in parallel will be 20 ohms with the voltage drop thereacross being insufiicient to provide enough current flow to adequately light the lamps. Let us further assume that a single detector is activated whose lamp happens to be burnt out so that the 1,000 ohm resistor is in series with the relay. Under this condition, the voltage drop across the relay will be insufficient to enable the relay to operate, resulting in a breakdown of the machine. Thus, it is seen that under the arrangement of FIG. 4, it is virtually impossible to select the components which will be satisfactorily operative under all possible conditions.

In order to overcome this serious problem, there may be provided, as shown in FIG. 4a, diode means 75 across relay 74. One of the characteristics of diodes such as diode means 75 is that regardless of the amount of current passing therethrough, the voltage thereacross remains substantially constant. Accordingly, the amount of current passing through relay 74 remains relatively constant regardless of how many detectors are activated at any time. Thus, the selection of a sufficiently sensitive relay 74 can easily be made without regard to the amount of current drawn by the detectors since the current flow therethrough will always be substantially the sarne and of a magnitude which is nevertheless sufficient to energize the relay. It will be understood that in order to provide for the requisite voltage across relay 74 it may be necessary to use three or more diodes in series instead of the two r with all corresponding elements being primed in A and double primed in A". The parallel arrangement of the control circuits for the various detectors is evident in FIG. 5 from which it will also be noted, as indicated above, that the more closed latch detectors are activated, the greater will be the current drawn from the power supply, amounting, in essence, to the sum total of the current passing through lead wires 62, 62', 62", etc. The power pack as shown in FIG. 5 enables the use of a single power supply which provides, simultaneously, sufficient current for all the detector lamps, regardless of how many are energized, while still providing the desired amount of current for activating the stop motion relay under all possible circumstances. More specifically, there is provided an AC supply 82 in series with diode 84 both of which are shunted by condenser 86. Accordingly, there is provided across terminals 88 and 90 a continuous supply of uni-directional current with grounded terminal 88 having the positive potential.

The operation of the circuitry in FIG. is as follows. When the knitting machine is operating normally, with all the detectors being unactivated, there is current flow from positive terminal 88 to ground, to terminal 92, through resistor 94, through the grid circuit of transistor amplifier 96, to terminal 98, and back to negative terminal 90. Such current flow triggers transistor amplifier 96 to maintain current flow therethrough from ground, terminal 92 and relay 100. Accordingly, it is seen that during the normal operation of the knitting machine, relay 100 is normally energized, retaining switch 102 in closed condition to maintain motor M normally energized. It will be noted here that whereas in FIG. 4 the stop motion relay is shown as being normally unenergized, it has been found preferable to have the stop motion relay normally energized, as shown in FIG. 5, so that if there is an accidental loose ground connection, it will de-energize the relay and stop the motor. With a normally unenergized relay as in FIG. 4, an accidental loose ground will render the faulty latch needle inoperative and maintain the motor running when it should be stopped because of the presence of a closed latch, or of excessive foreign matter on the needle.

When one or more closed latch detectors is activated, there will be current flow from temiinal 88 through ground, through circuitry A of the detector or detectors which have been activated, through lead wire 62, terminals 104, 106, diodes 108, 110, terminal 112, terminal 98 and negative terminal 90. The amount of current flow will be dependent on the number of detectors which have been activated, that is, the greater the number of detectors, the larger the current drawn from the power supply. As previously discussed in connection with FIG. 4a, regardless of the amount of current passing through diodes 108 and 110, the voltage drop thereacross remains relatively constant. Accordingly, though the current flow through diodes 108 and 110 may be quite low (if for example only one detector was activated whose light 48 happens to be out whereby the current drawn is quite low because of the high resistance of resistor 68), or quite high in the event that a large number of detectors are activated simultaneously, the potential across diodes 108 and 110, i.e., across terminals 106 and 112 is relatively constant. There is provided across terminals 106 and 112, resistor 114 and the grid circuit of transistor amplifier 116 so that whenever one or more detectors are activated, there will be current flow through the triggering circuit of transistor 116 which will render the latter conductive and provide a current path from ground to terminal 92, resistor 94, transistor 116, terminal 112, terminal 98 and the negative terminal of the power supply. Such current flow in effect short circuits the grid circuit of transistor 96 to render the latter non-conducting and de-energize stop motion relay 100, which, in turn, interrupts the drive of motor M.

The power pack of FIG. 5 is thus seen to enable the use of a single power supply which simultaneously provides all the current that may be required for the detector lights while at the same time making provision for de-energizing the motor without posing any difficulties regarding the selection of the relay or any of the other components within the circuit.

Another embodiment of a power pack is shown in FIG. 6 wherein there are shown detector circuits A, A, A, identical to those illustrated in FIG. 5. Arranged in symmetry with circuits A, A and A are detector circuits B, B and B. Circuit B is identical in all respects to circuit A with the sole exception that lead wires 62b, 62b and 62b are grounded, with current flow through detector circuit B being from terminal 118 to ground. AC power supply 120 defines with diode 122 and condenser 124 a DC supply between terminal 126 and terminal 128. Terminal 126 is grounded so that the potential at terminal 128 is negative with respect to ground. Similarly, AC supply 120 defines with diode 130 and condenser 132 another DC supply between terminals 126 and 134, the latter being positive with respect to ground.

The operation of the circuitry in FIG. 6 is as follows. When the knitting machine is operating normally with all the faulty needle detectors (A, A, A and B, B, B" being unactivated, there is current flow from positive terminal 134, through terminal 136, through the grid circuit of transistor amplifier 96b, resistor 94, grid circuit of transistor 96a, terminal 138 and negative terminal 128. Such current flow renders transistors 96b and 96a conductive to provide current flow through relay 100 which in turn retains switch 102 in closed condition to maintain motor M normally energized.

When one or more closed latch detectors in group A is activated, there will be current flow from terminal 126 through ground, through circuitry A of the faulty needle detector or detectors which have been activated, through lead wire 62, terminal 106a, diodes 108a, 110a, terminals 112a, 138 and to negative terminal 128, to provide all the current needed to light lamps 48. As previously set forth, regardless of the number of detectors A which are activated, there will be a constant current flow from terminal 106a through resistor 114a, gn'd circuit of transistor 116a, terminal 112a, which current How will trigger transistor amplifier 116a to render the latter conductive and thereby short circuit the grid circuit of transistor amplifier 96a. Such short circuiting of the grid circuit of transistor amplifier 96a will render the latter non-conductive to interrupt current flow through relay 100 and open switch 102 to de-energize the motor.

Similarly, in the event that one or more detector circuits in group B is activated, there will be current flow from positive terminal 134, terminal 136, terminal 112b, diodes 110b and 108b, terminal 106b, through the activated detector circuit B, lead wire 62b, ground, and back to terminal 126 of the power supply. At the same time, regardless of the amount of current drawn by detectors B, B there is a constant current flow from terminal 112b through grid circuit of transistor amplifier 116b, resistor 114b to terminal 106b which renders transistor amplifier 116b conductive and short circuits the grid circuit of transistor amplifier 96b to render the latter non-conductive. Such resulting nonconductivity of transistor amplifier 96b interrupts current flow to stop motion relay 100 which in turn interrupts the energization of drive motor M.

Thus it is seen that the power pack of FIG. 6 provides with a single power supply all the requisite current for lighting the lights in each and every detecting device which has been activated, while at the same time providing the requisite power for controllingthe stop motion relay. It will also be notedthat the power pack of FIG. 6' is symmetrical and electrically redundant. Accordingly, it' is substantially a fail safe system so that if anything 8 s wrong, either because of the activation of any of the detectors or because of the unintentional disconnection of any of the components, the stop motion relay will be efiective to stop the machine and prevent damage thereto. I

While detector circuit B has been shown as being a defective latch needle detector, since the switch defined by 36b-40b is closed in response to the deflection of a feeler similar to feeler 28, the power pack circuitry in FIG. 6 is equally compatible with any other detectors in the knitting machine which when activated are intended to stop the energization of the motor and light a lamp on the detector. For example, a conventional knitting machine is provided with detecting devices which detect broken yarn or yarn under tension in excess of a predetermined value such as shown in U.S. Pat. No. 3,257,518 assigned to the assignee hereof. Such yarn fault detectors include a switch which is closed in response to the detection of the yarn defect and a light which is intended to be simultaneously lit. Accordingly, any such detectors can be powered by the same power pack as described in FIG. 6 either among detectorsA or detectors B, as well as by the power pack disclosed in FIG. 5.

While we have herein shown and described the preferred embodiments of our invention, it will be understood that the invention may be embodied otherwise than as herein specifically illustrated or described, and that in the illustrated embodiments certain changes in the details of construction and in the form and arrangement of parts may be made without departing from the underlying idea or principles of this invention within the scope of the appended claims.

Having thus described. our invention, what we claim and desire to secure by letters patent is:

1. Means for detecting a defective latch needle condition in a knitting machine having a rotary needle cylinder carrying a plurality of latch needles, comprismg a. a feeler adapted to be mounted in the path of movement of said needles so as to be displaced by a latch needle in said defective condition,

b. said feeler being insulatingly carried by a flexible member whereby displacement of said feeler by a latch needle in defective condition causes flexing of said flexible member,

c. a core mounted in insulated normally spaced relation with said flexible member and adapted to be electrically contacted thereby upon flexing of said flexible member in response to displacement of said feeler,

d. said core and flexible member cooperating to define a normally open electrical switch which is closed in response to displacement of said feeler by a closed latch, and

e. electrical control means electrically connected to said switch and operative, in response to the closing of said switch, to de-energize the drive means for said knitting machine.

2. The combination according to claim 1, wherein said flexible member is a coil spring and said feeler is carried by a plug closing one end of said coil spring.

3. The combination according to claim 1, wherein there is further provided a lamp adapted to be energized by said electrical control means in response to the closing of said switch.

4. The combination according to claim 1, wherein said electrical control means comprise a. a gate controlled electronic device having the gate circuit thereof in series with said switch, said device and switch being supplied by a power source whereby the closing of said switch provides current flow through said gate circuit thereby rendering said device conductive, and

b. means responsive to said electronic device being conductive for de-energizing the drive means of said knitting machine.

5. The combination according to claim 3, wherein said electrical control means comprise a. a gate controlled electronic device having the gate circuit thereof in series with said switch, said electronic device and switch being supplied by a power source whereby the closing of said switch provides current flow through said gate circuit thereby rendering said electronic device conductive, and

b. means responsive to said electronic device being conductive for de-energizing the drive means of said knitting machine.

6. Means for detecting a defective latch needle condition in a knitting machine having a rotary needle cylinder carrying a plurality of latch needles, comprisa. a tubular housing,

b. a coil spring insulatingly mounted in said housing and extending outwardly of one end thereof,

a feeler insulatingly carried by said spring and disposed in the path of movement of said needles so as to be displaced by a latch needle in said defective condition,

. a core mounted in insulated normally spaced relation within said coil and adapted to be electrically contacted thereby upon flexing of said coil in response to displacement of said feeler,

. said core and coil cooperating to define a normally open electrical switch which is closed in response to displacement of said feeler by a closed latch,

. a lamp carried in said housing adjacent the other end thereof, and

. electrical control means electrically connected to said switch and operative, in response to the closing of said switch, to de-energize drive means for said knitting machine and to energize said lamp.

7. The combination according to claim 6, wherein there is further provided a. a lens for said lamp mounted in said housing, and

b. cooperating means on said lens and said housing normally biased into engagement with each other to define a normally closed reset switch.

8. The combination according to claim 6, wherein said electrical control means comprise a. a gate controlled electronic device having the gate circuit thereof in series with said switch, said electronic device and switch being supplied by a power source whereby the closing of said switch provides current flow through said gate circuit thereby rendering said electronic device conductive, and

b. means responsive to said electronic device being conductive for de-energizing the drive means of said knitting machine.

9. The combination according to claim 7, wherein said electrical control means comprise a. a gate controlled electronic device having the gate circuit thereof in series with said switch, said electronic device and switch being supplied by a power source whereby the closing of said switch provides current flow through said gate circuit thereby rendering said electronic device conductive, and

b. means responsive to said electronic device being conductive for de-energizing the drive means of said knitting machine.

10. Means for detecting a defective latch needle condition in a knitting machine having a rotary needle cylinder carrying a plurality of latch needles, comprismg a. a tubular housing,

b. a coil spring insulatingly mounted in said housing and extending outwardly of one end thereof,

c. a feeler insulatingly carried by said spring and disposed in the path of movement of said needles when closed so as to be displaced by a latch needle in said defective condition,

. a core mounted in insulated normally spaced relation within said coil and adapted to be electrically contacted thereby upon flexing of said coil in response to displacement of said feeler,

. said core and coil cooperating to define a normally open electrical switch which is closed in response to displacement of said feeler by a closed latch,

f. a lamp carried in said housing adjacent the other end thereof,

. said housing defining a compartment therein intermediate said ends thereof, and electrical control means disposed in said compartment and connected to said switch and said lamp, said electrical control means being operative, in response to the closing of said switch, to de-energize the drive means for said knitting machine and to energize said lamp.

11. The combination according to claim 10, wherein there is further provided a. a lens for said lamp mounted in said housing, and

b. cooperating means on said lens and said housing normally biased into engagement with each other to define a normally closed reset switch.

12. The combination according to claim 11, wherein said electrical control means comprise a. a gate controlled electronic device having the gate circuit thereof in series with said switch, said electronic device and switch being supplied by a power source whereby the closing of said switch provides current flow through said gate circuit thereby rendering said electronic device conductive, and

b. means responsive to said electronic device being conductive for de-energizing the drive means of said knitting machine.

13. The combination according to claim 7, wherein said cooperating means comprise a reset ring secured to the rim of the lens, an end ring secured to said housing, and a spring acting against said lens and urging said reset ring into' engagement with said end ring.

14. The combination according to claim 13, wherein said electrical control means comprise a. a gate controlled electronic device having the gate circuit thereof in series with said switch, said electronic device and switch being supplied by a power source whereby the closing of said switch provides current flow through said gate circuit thereby rendering said electronic device conductive, and

b. means responsive to said electronic device being conductive for de-energizing the drive means of said knitting machine.

15. The combination according to claim 1, wherein said flexible member and said core are magnetically retained in engagement following said electrical contact upon flexing of said flexible member.

16. A control network for a knitting machine provided with a plurality of fault detecting circuits in electrical parallel relation to each other, with each circuit including a switch closed upon the detection of a fault and a lamp shunted by a resistance, comprising a. a power source connected to said parallel circuits and providing current flow to any of said circuits in response to the closing of the associated switch, thereby energizing the associated lamp,

b. diode means interposed between said power source and said parallel circuits whereby the current flow therethrough is equal to the sum of current flow through said fault detecting circuits, said diode means providing a substantially constant voltage drop thereacross independent of the amount of current flow therethrough, and

. electrical means shunting said diode means, said shunting means receiving substantially constant current flow independently of the current flow through said diode means,

. said shunting means being operative, when energized by the current flow therethrough, to cause de-energization of the drive means for said knitting machine.

17. A control network according to claim 16, wherein said electrical shunting means comprise a relay which, when energized, causes de-energization of the drive means for the knitting machine.

18. A control network according to claim 16, wherein said electrical shunting means comprise the grid circuit of a first electronic amplifier, whereby current flow therethrough renders said first electronic amplifier conductive, and wherein there is further provided a. a normally conductive second electronic amplifier electrically related to said first electronic amplifier so that said second electronic amplifier becomes non-conductive when said first electronic amplifier is conductive,

b. a relay in series with said second electronic amplifier and energized when said second electronic amplifier is conductive, said relay being operative, when de-energized, to interrupt the energization of the drive means for the knitting machine,

whereby the closing of any one of said switches causes current flow through the grid circuit of said first electronic amplifier, rendering said first amplifier conductive and said second amplifier non-conductive, thereby causing de-energization of said relay and interruption of the drive means for the knitting machine.

19. Means for detecting a defective latch needle condition in a knitting machine having a rotary needle cylinder carrying a plurality of latch needles, comprismg a. a-feeler. adapted to be mounted in the path of movement of said needles so as to be displaced by a latch needlein said defective condition,

b. said feeler being insulatingly carried by a flexible member whereby displacement of said feeler by a latch needle in defective condition causes flexing of said flexible member,

c. a core mounted in insulated normally spaced relation with said flexible member and adapted to be electrically contacted thereby upon flexing of said flexible member in response to displacement of said feeler, 1

d. said core and flexible member cooperating to define a normally open electrical switch which is closed in response to displacement of said feeler by a closed latch,

e. a lamp shunted by a'resistance, said lamp and switch defining a fault detecting circuit,

f. a power source connected to said fault detecting circuit and providing current flow therethrough in response to the closing of said switch, thereby energizing said lamp,

'g, diode means interposed between said power source and said fault detecting circuit, said diode means providing a substantially constant voltage drop thereacross independent of the amount of current flow therethrough, and

h. electrical means shunting said diode means, said shunting means receiving substantially constant current flow independently of the current flow through said diode means,

i. said shunting means being operative, when energized by the current flow therethrough, to cause de-energization of the drive means for said knitting machine.

20. The combination according to claim 19, wherein saidelectrical shunting means comprise a relay which, when energized, causes de-energization of the drive means for the knitting machine.

21. The combination according to claim 19, wherein said electrical shunting means comprise the grid circuit of a first electronic amplifier, whereby current flow therethrough renders said first electronic amplifier conductive, and wherein there is further provided a. a normally conductive second electronic amplifier electrically related to said first electronic amplifier so that said second electronic amplifier becomes non-conductive when said first electronic amplifier is conductive,

b. a relay in series with said second electronic amplifier and energized when said second electronic amplifier is conductive, said relay being operative, when de-energized, to interrupt the energization of the drive means for the knitting machine,

whereby the closing of any one of said switches causes current flow through the grid circuit of said first electronic amplifier, rendering said first amplifier conductive and said second amplifier non-conductive, thereby causing de-energization of said relay and interruption of the drive means for the knitting machine.

22. A control network for a knitting machine provided with two sets of fault detecting circuits, each of which sets comprises a plurality of fault detecting circuits in parallel relation to each other, with each circuit including a switch closed upon the detection of a fault and a lamp shunted by a resistance, comprising a. a power source connected to said sets and providing current flow to any of said circuits in response to the closing of the associated switch, thereby energizing the associated lamp, b. first diode means interposed between said power sourceand the first of said sets whereby the current flow therethrough is equal to the sum of current flow through the fault detecting circuits in said first set, said first diode means providing a substantially constant voltage drop thereacross independent of the amount of current flow therethrough,

. second diode means interposed between said power source and the 'second of said sets whereby the current flow therethrough is equal to the sum of current flow through the fault detecting circuits in said second set, said second diode means providing a substantially constant voltage drop thereacross independent of the amount of current flow therethrough,

. first and second electrical means shunting, respectively, said first and second diode means, said shunting means receiving substantially constant current flow independently of the current flow through the associated diode means,

. each of said shunting means being operative, when energized by the current flow therethrough, to cause de-energization of the drive means for said knitting machine.

23. A control network according to claim 22, wherein said first electrical shunting means comprise the grid circuit of a first electronic amplifier, whereby current flow therethrough renders said first electronic amplifier conductive and wherein said second electrical shunting means comprise the grid circuit of a second electronic amplifier, whereby current flow therethrough renders said second electronic amplifier conductive, and wherein there is further provided a. a normally conductive third electronic amplifier electrically related to said first electronic amplifier so that said third electronic amplifier becomes non-conductive when said first electronic amplifier is conductive,

. a normally conductive fourth electronic amplifier electrically related to said second electronic amplifier so that said fourth electronic amplifier becomes non-conductive when said second electronic amplifier is conductive,

. a relay in series with said second and fourth electronic amplifiers whereby it is energized only when both said second and fourth electronic amplifiers are conductive, said relay being operative, when de-energized, to interrupt the energization of the drive means for the knitting machine.

whereby the closing of any of the switches in the first set of fault detecting circuits causes current flow through the grid circuit of said first electronic amplifier, rendering said first amplifier conductive and said third amplifier non-conductive, thereby causing deenergization of said relay and interruption of the drive means for the knitting machine, and whereby the closing of any of the switches in the second set of fault detecting circuits causes current flow through the grid circuit of said second electronic amplifier, rendering said second amplifier conductive and said fourth amplifier non-conductive, thereby causing de-energization of knitting machine. 

1. Means for detecting a defective latch needle condition in a knitting machine having a rotary needle cylinder carrying a plurality of latch needles, comprising a. a feeler adapted to be mounted in the path of movement of said needles so as to be displaced by a latch needle in said defective condition, b. said feeler being insulatingly carried by a flexible member whereby displacement of said feeler by a latch needle in defective condition causes flexing of said flexible member, c. a core mounted in insulated normally spaced relation with said flexible member and adapted to be electrically contacted thereby upon flexing of said flexible member in response to displacement of said feeler, d. said core and flexible member cooperating to define a normally open electrical switch which is closed in response to displacement of said feeler by a closed latch, and e. electrical control means electrically connected to said switch and operative, in response to the closing of said switch, to de-energize the drive means for said knitting machine.
 2. The combination according to claim 1, wherein said flexible member is a coil spring and said feeler is carried by a plug closing one end of said coil spring.
 3. The combination according to claim 1, wherein there is further provided a lamp adapted to be energized by said electrical control means in response to the closing of said switch.
 4. The combination according to claim 1, wherein said electrical control means comprise a. a gate controlled electronic device having the gate circuit thereof in series with said switch, said device and switch being supplied by a power source whereby the closing of said switch provides current flow through said gate circuit thereby rendering said device conductive, and b. means responsive to said electronic device being conductive for de-energizing the drive means of said knitting machine.
 5. The combination according to claim 3, wherein said electrical control means comprise a. a gate controlled electronic device having the gate circuit thereof in series with said switch, said electronic device and switch being supplied by a power source whereby the closing of said switch provides current flow through said gate circuit thereby rendering said electronic device conductive, and b. means responsive to said electronic device being conductive for de-energizing the drive means of said knitting machine.
 6. Means for detecting a defective latch needle condition in a knitting machine having a rotary needle cylinder carrying a plurality of latch needles, comprising a. a tubular housing, b. a coil spring insulatingly mounted in said housing and extending outwardly of one end thereof, c. a feeler insulatingly carried by said spring and disposed in the path of movement of said needles so as to be displaced by a latch needle in said defective condition, d. a core mounted in insulated normally spaced relation within said coil and adapted to be electrically contacted thereby upon flexing of said coil in response to displacement of said feeler, e. said core and coil cooperating to define a normally open electrical switch which is closed in response to displacement of said feeler by a closed latch, f. a lamp carried in said housing adjacent the other end thereof, and g. electrical control means electrically connected to said switch and operative, in response to the closing of said switch, to de-energize drive means for said knitting machine and to energize said lamp.
 7. The combination according to claim 6, wherein there is further provided a. a lens for said lamp mounted in said housing, and b. cooperating means on said lens and said housing normally biased into engagement with each other to define a normally closed reset switch.
 8. The combination according to claim 6, wherein said electrical control means comprise a. a gate controlled electronic device having the gate circuit thereof in series with said switch, said electronic device and switch being supplied by a power source whereby the closing of said switch provides current flow through said gate circuit thereby rendering said electronic device conductive, and b. means responsive to said electronic device being conductive for de-energizing the drive means of said knitting machine.
 9. The combination according to claim 7, wherein said electrical control means comprise a. a gate controlled electronic device having the gate circuit thereof in series with said switch, said electronic device and switch being supplied by a power source whereby the closing of said switch provides current flow through said gate circuit thereby rendering said electronic device conductive, and b. means responsive to said electronic device being conductive for de-energizing the drive means of said knitting machine.
 10. Means for detecting a defective latch needle condition in a knitting machine having a rotary needle cylinder carrying a plurality of latch needles, comprising a. a tubular housing, b. a coil spring insulatingly mounted in said housing and extending outwardly of one end thereof, c. a Feeler insulatingly carried by said spring and disposed in the path of movement of said needles when closed so as to be displaced by a latch needle in said defective condition, d. a core mounted in insulated normally spaced relation within said coil and adapted to be electrically contacted thereby upon flexing of said coil in response to displacement of said feeler, e. said core and coil cooperating to define a normally open electrical switch which is closed in response to displacement of said feeler by a closed latch, f. a lamp carried in said housing adjacent the other end thereof, g. said housing defining a compartment therein intermediate said ends thereof, and h. electrical control means disposed in said compartment and connected to said switch and said lamp, said electrical control means being operative, in response to the closing of said switch, to de-energize the drive means for said knitting machine and to energize said lamp.
 11. The combination according to claim 10, wherein there is further provided a. a lens for said lamp mounted in said housing, and b. cooperating means on said lens and said housing normally biased into engagement with each other to define a normally closed reset switch.
 12. The combination according to claim 11, wherein said electrical control means comprise a. a gate controlled electronic device having the gate circuit thereof in series with said switch, said electronic device and switch being supplied by a power source whereby the closing of said switch provides current flow through said gate circuit thereby rendering said electronic device conductive, and b. means responsive to said electronic device being conductive for de-energizing the drive means of said knitting machine.
 13. The combination according to claim 7, wherein said cooperating means comprise a reset ring secured to the rim of the lens, an end ring secured to said housing, and a spring acting against said lens and urging said reset ring into engagement with said end ring.
 14. The combination according to claim 13, wherein said electrical control means comprise a. a gate controlled electronic device having the gate circuit thereof in series with said switch, said electronic device and switch being supplied by a power source whereby the closing of said switch provides current flow through said gate circuit thereby rendering said electronic device conductive, and b. means responsive to said electronic device being conductive for de-energizing the drive means of said knitting machine.
 15. The combination according to claim 1, wherein said flexible member and said core are magnetically retained in engagement following said electrical contact upon flexing of said flexible member.
 16. A control network for a knitting machine provided with a plurality of fault detecting circuits in electrical parallel relation to each other, with each circuit including a switch closed upon the detection of a fault and a lamp shunted by a resistance, comprising a. a power source connected to said parallel circuits and providing current flow to any of said circuits in response to the closing of the associated switch, thereby energizing the associated lamp, b. diode means interposed between said power source and said parallel circuits whereby the current flow therethrough is equal to the sum of current flow through said fault detecting circuits, said diode means providing a substantially constant voltage drop thereacross independent of the amount of current flow therethrough, and c. electrical means shunting said diode means, said shunting means receiving substantially constant current flow independently of the current flow through said diode means, d. said shunting means being operative, when energized by the current flow therethrough, to cause de-energization of the drive means for said knitting machine.
 17. A control network according to claim 16, wherein said electrical shunting means comprise a relaY which, when energized, causes de-energization of the drive means for the knitting machine.
 18. A control network according to claim 16, wherein said electrical shunting means comprise the grid circuit of a first electronic amplifier, whereby current flow therethrough renders said first electronic amplifier conductive, and wherein there is further provided a. a normally conductive second electronic amplifier electrically related to said first electronic amplifier so that said second electronic amplifier becomes non-conductive when said first electronic amplifier is conductive, b. a relay in series with said second electronic amplifier and energized when said second electronic amplifier is conductive, said relay being operative, when de-energized, to interrupt the energization of the drive means for the knitting machine, whereby the closing of any one of said switches causes current flow through the grid circuit of said first electronic amplifier, rendering said first amplifier conductive and said second amplifier non-conductive, thereby causing de-energization of said relay and interruption of the drive means for the knitting machine.
 19. Means for detecting a defective latch needle condition in a knitting machine having a rotary needle cylinder carrying a plurality of latch needles, comprising a. a feeler adapted to be mounted in the path of movement of said needles so as to be displaced by a latch needle in said defective condition, b. said feeler being insulatingly carried by a flexible member whereby displacement of said feeler by a latch needle in defective condition causes flexing of said flexible member, c. a core mounted in insulated normally spaced relation with said flexible member and adapted to be electrically contacted thereby upon flexing of said flexible member in response to displacement of said feeler, d. said core and flexible member cooperating to define a normally open electrical switch which is closed in response to displacement of said feeler by a closed latch, e. a lamp shunted by a resistance, said lamp and switch defining a fault detecting circuit, f. a power source connected to said fault detecting circuit and providing current flow therethrough in response to the closing of said switch, thereby energizing said lamp, g. diode means interposed between said power source and said fault detecting circuit, said diode means providing a substantially constant voltage drop thereacross independent of the amount of current flow therethrough, and h. electrical means shunting said diode means, said shunting means receiving substantially constant current flow independently of the current flow through said diode means, i. said shunting means being operative, when energized by the current flow therethrough, to cause de-energization of the drive means for said knitting machine.
 20. The combination according to claim 19, wherein said electrical shunting means comprise a relay which, when energized, causes de-energization of the drive means for the knitting machine.
 21. The combination according to claim 19, wherein said electrical shunting means comprise the grid circuit of a first electronic amplifier, whereby current flow therethrough renders said first electronic amplifier conductive, and wherein there is further provided a. a normally conductive second electronic amplifier electrically related to said first electronic amplifier so that said second electronic amplifier becomes non-conductive when said first electronic amplifier is conductive, b. a relay in series with said second electronic amplifier and energized when said second electronic amplifier is conductive, said relay being operative, when de-energized, to interrupt the energization of the drive means for the knitting machine, whereby the closing of any one of said switches causes current flow through the grid circuit of said first electronic amplifier, rendering said first amplifier conductive and said second amplifiEr non-conductive, thereby causing de-energization of said relay and interruption of the drive means for the knitting machine.
 22. A control network for a knitting machine provided with two sets of fault detecting circuits, each of which sets comprises a plurality of fault detecting circuits in parallel relation to each other, with each circuit including a switch closed upon the detection of a fault and a lamp shunted by a resistance, comprising a. a power source connected to said sets and providing current flow to any of said circuits in response to the closing of the associated switch, thereby energizing the associated lamp, b. first diode means interposed between said power source and the first of said sets whereby the current flow therethrough is equal to the sum of current flow through the fault detecting circuits in said first set, said first diode means providing a substantially constant voltage drop thereacross independent of the amount of current flow therethrough, c. second diode means interposed between said power source and the second of said sets whereby the current flow therethrough is equal to the sum of current flow through the fault detecting circuits in said second set, said second diode means providing a substantially constant voltage drop thereacross independent of the amount of current flow therethrough, d. first and second electrical means shunting, respectively, said first and second diode means, said shunting means receiving substantially constant current flow independently of the current flow through the associated diode means, e. each of said shunting means being operative, when energized by the current flow therethrough, to cause de-energization of the drive means for said knitting machine.
 23. A control network according to claim 22, wherein said first electrical shunting means comprise the grid circuit of a first electronic amplifier, whereby current flow therethrough renders said first electronic amplifier conductive and wherein said second electrical shunting means comprise the grid circuit of a second electronic amplifier, whereby current flow therethrough renders said second electronic amplifier conductive, and wherein there is further provided a. a normally conductive third electronic amplifier electrically related to said first electronic amplifier so that said third electronic amplifier becomes non-conductive when said first electronic amplifier is conductive, b. a normally conductive fourth electronic amplifier electrically related to said second electronic amplifier so that said fourth electronic amplifier becomes non-conductive when said second electronic amplifier is conductive, c. a relay in series with said second and fourth electronic amplifiers whereby it is energized only when both said second and fourth electronic amplifiers are conductive, said relay being operative, when de-energized, to interrupt the energization of the drive means for the knitting machine. whereby the closing of any of the switches in the first set of fault detecting circuits causes current flow through the grid circuit of said first electronic amplifier, rendering said first amplifier conductive and said third amplifier non-conductive, thereby causing de-energization of said relay and interruption of the drive means for the knitting machine, and whereby the closing of any of the switches in the second set of fault detecting circuits causes current flow through the grid circuit of said second electronic amplifier, rendering said second amplifier conductive and said fourth amplifier non-conductive, thereby causing de-energization of said relay and interruption of the drive means for the knitting machine. 